Wira 1.5 4G15 Exhaust Piping

[freshbatman]

Dear friends,

I owned 2005 Wira sedan,1.5GLi Auto.
Last year,i did convert my gear box to 1.5 manual transmission gear box + 1.6 clutch plate.
Now,i'm thinking for the piping modification.
I heard so many idea's from so many people.Some say,just go for 4-2-1 extractor only.Some say put 2 bullet,get off the catcon.Some say get off the muffler,do straight piping to the end.

I'm clueless rite now.

As Z2H has experts on mod,could u guys recommend me the best way of exhaust mod for my car,in order to get extra power,plus standard fuel consumption(if possible)...?
I need both pick-up and power,coz i don't want to lose any of that.

And,please recommend the worksyop for good exhaust piping job.
FYI,im staying in Penang.

Thanx in advance.

 

[tofu_manic]

not kira expert la....but just my 2 sen

if urs is a Wira SE then stick with ur original 4-2-1 which is mandrel-bent

as for piping, just go for a 1.7 to 1.8 inch from front to back (going slitely larger brings the powerband in later, better breathing up top at the sacrifice of the bottom and vice versa)

dont have to put any bullets

have it go straight through the back, so get a straight flow exhaust tong, preferably with as large a tong as u can get for more noise suppression without losing any flow

if u wanna suppress more of the sound, put a tong in the middle, but get a straight through one, not the swirling type

Cheers!

 

[SkYwAlKeR]

4-2-1 extractor...
1.8" piping... original route...
single midbullet to replace ur catcon...
1.8" inlet straight flow muffler....

 

[PEK3442]

if Auto..better use S-flow mufler...
other its ok..4-2-1..1.6" to 1.8" piping follow the 'longkang' and 1 bullet.
Penang have a lot 'kedai ekzos'
PM me if U wan to know..

 

[tofu_manic]

if Auto..better use S-flow mufler...
other its ok..4-2-1..1.6" to 1.8" piping follow the 'longkang' and 1 bullet.
Penang have a lot 'kedai ekzos'
PM me if U wan to know..

our brader using manual trans edi

eh threadstarter gone haha

 

[4gManiaC]

4-2-1 extractor,2" piping,1 centre bullet,straight piping(but sure not pass jpj),better goes for original route

 

[civic EdGe]

On the side topic, what are the difference between these 3 types of bullet?
1. Swirling type
2. "Valve type"
3. Straight through

The most common one that i can see around is the swirling type....
But from my opinion, if the air really does swirl through the bullet, wouldnt it be travelling in a longer distance comparing to taking a "straight" route?

And there's bullets with "valves", dunno wats the correct term for this but you can see humps coming out from the edge of the circle when you see through the center hole.... at first looks like more restriction, but on second thought, maybe it will bump up the velocity of the exitting gas?

 

[tofu_manic]

4-2-1 extractor,2" piping,1 centre bullet,straight piping(but sure not pass jpj),better goes for original route

Powerzone did dyno their maxed out 4g15 NA iswara, and with 2 inch piping, it lost a coupla hps as compared to with a 1.7-1.8 inch piping

im guessing a 4g15 with specs for drag racing, meaning effective at only mid-high rpm would benefit from a 2 inch piping setup

On the side topic, what are the difference between these 3 types of bullet?
1. Swirling type
2. "Valve type"
3. Straight through

The most common one that i can see around is the swirling type....
But from my opinion, if the air really does swirl through the bullet, wouldnt it be travelling in a longer distance comparing to taking a "straight" route?

And there's bullets with "valves", dunno wats the correct term for this but you can see humps coming out from the edge of the circle when you see through the center hole.... at first looks like more restriction, but on second thought, maybe it will bump up the velocity of the exitting gas?

the smoother, the easier the gasses flow out, the better it is, provided u have the right piping size

u wont see a jap aftermarket exhaust system with a swirling bullet, neva seen one

 

[loose_end]

Powerzone did dyno their maxed out 4g15 NA iswara, and with 2 inch piping, it lost a coupla hps as compared to with a 1.7-1.8 inch piping

im guessing a 4g15 with specs for drag racing, meaning effective at only mid-high rpm would benefit from a 2 inch piping setup



the smoother, the easier the gasses flow out, the better it is, provided u have the right piping size

u wont see a jap aftermarket exhaust system with a swirling bullet, neva seen one

So , the best is straight through?

 

[tofu_manic]

just based on what i noe so far la, the straighter, smoother it is...the better

 

[4gManiaC]

Bump:

Powerzone did dyno their maxed out 4g15 NA iswara, and with 2 inch piping, it lost a coupla hps as compared to with a 1.7-1.8 inch piping

im guessing a 4g15 with specs for drag racing, meaning effective at only mid-high rpm would benefit from a 2 inch piping setup

owh,really??if that's the case go for 1.7"/1.8" only..thx for sharing..

by the way i think swirling types of centre bullet gives slightly more high power as it compress the exhaust flow..

 

[SkYwAlKeR]

owh,really??if that's the case go for 1.7"/1.8" only..thx for sharing..

by the way i think swirling types of centre bullet gives slightly more high power as it compress the exhaust flow..

why wanna compress the exhaust flow??... jz let it flow smoothly out lo...

 

[JINEIL2EN]

my setup,
4-2-1, single bullet, 1.8" inlet piping(follow stock bended), rear 2" inlet with S-Flow FGK muffler...

 

[ARSSS]

im guessing a 4g15 with specs for drag racing, meaning effective at only mid-high rpm would benefit from a 2 inch piping setup



the smoother, the easier the gasses flow out, the better it is, provided u have the right piping size

u wont see a jap aftermarket exhaust system with a swirling bullet, neva seen one

I dont think u r entirely correct..

You need some restriction in the exhaust to build up compression in the chamber for NA cars, but it has to be at proper timing, that's why S flow exhaust give more HP for NA/auto. For turbo charged u always need bigger piping & straight flow..

S flow will helps to gain top speed and fuel efficiency.. but at expense of low power band and torque..

for your info : HKS also produce Hi power S-flow pipe.. cheers..

 

[SkYwAlKeR]

I dont think u r entirely correct..

You need some restriction in the exhaust to build up compression in the chamber for NA cars, but it has to be at proper timing, that's why S flow exhaust give more HP for NA/auto. For turbo charged u always need bigger piping & straight flow..

S flow will helps to gain top speed and fuel efficiency.. but at expense of low power band and torque..

for your info : HKS also produce Hi power S-flow pipe.. cheers..

sorry to interupt... u arent entirely correct as well...

yes, some restriction is needed for NA cars... without it, u will feel emptiness in lower revs without much moving torque... u'll only notice revs climb fast but not ur speed....

this is true especially for auto tranny because u cant choose exactly which rpm to shift up... means u will suffer from bad low end torque with constant revving but speed maintain low...

turbo charge cars do in fact has limitation in exhaust piping... this affects the turbo lag and how fast the turbine spools up...

for cars running around street, abit smaller piping with useful exhaust gas restriction helps the car to pickup speed at low rpm...

for drag/track cars running high rpm all the time, smoother exhaust flow allows exhaust gas exits as fast as possible....

 

[4gManiaC]

why wanna compress the exhaust flow??... jz let it flow smoothly out lo...

i think compress is good for back pressure... n again, correct me if i'm wrong bcoz i'm getting confuse right now..:hmmmm:

 

[fstr]

i use 2 inch last time on my 1.3, any problem??

 

[tofu_manic]

I dont think u r entirely correct..

You need some restriction in the exhaust to build up compression in the chamber for NA cars, but it has to be at proper timing, that's why S flow exhaust give more HP for NA/auto. For turbo charged u always need bigger piping & straight flow..

S flow will helps to gain top speed and fuel efficiency.. but at expense of low power band and torque..

for your info : HKS also produce Hi power S-flow pipe.. cheers..

yeap, i understand where you are coming from

but in my earlier statement, i did type this: 'the smoother, the easier the gasses flow out, the better it is, provided u have the right piping size'

here when i sed the smoother and easier the gasses flow....i was referring to lesser bends and kinks in the piping so things flow smoothly, then i tokked about the piping size

from what ive learnt here n there la :P u dont really need the 'compressing of exhaust gasses'...but what u do need is the 'siphoning' effect of the exhaust pulses...at the intended power range...(e.g. high up in the powerband, or down low)..which can be achieved with the right piping size...

e.g. at the right piping size, at the intended power range, an exhaust pulse which exits the engine creates vacuum right behind it, and if all is ideal, it will help to 'pull' the next exhaust pulse, thus making it easier for the gasses to leave

with a smaller exhaust pipe, this effect is achieved earlier, so more torque down low...but restrictive up top (which skywalker referred to as a bit more 'restriction' for streetability)

with a larger exhaust pipe, this effect is achieved later, so more torque from mid to top, but lesser torque down low (which skywalker referred to as lesser restriction, good flow for all-out power)

could u really prove that s-flow exhausts give more hp for NAs as compared to straight through exhausts? even if hks did make an s-flow exhaust for NA, the majority of exhausts made for performance NA engines are straight through...and hks makes many many straight through exhausts as well

question, how does a more restrictive exhaust (e.g. with an s-flow exhaust) give u a higher top speed at higher rpm, where exhaust gasses are rushing to escape the combustion chamber at top speed, but then suddenly has to slam into an s-shaped corridor first?

in high rpm applications, like drag racing, ive never seen an NA drag car use an s-flow exhaust...just a thought

interesting discussion, though hehe im not too sure myself, definitely will have mistakes here and there

Cheers!

p.s fstrader...ur monster 4g13 was with twin carburettors with an all-out 292 degree billet racing cam...how to compare :P

 

[SkYwAlKeR]

i use 2 inch last time on my 1.3, any problem??

ur engine spec is different mar sifoo....

 

[K_Takuya]

please correct me if im wrong... at top speed, s flow is better than straight flow?

Bump: please correct me if im wrong... at top speed, s flow is better than straight flow?